JPH07120049A - Air conditioner - Google Patents

Abstract

PURPOSE:To sense an outside air temperature without the needs for an outside air temperature sensor, require no consideration for a setting place and make the highly reliable detection of the outside air temperature possible without being adversely affected by sunshine and the like while lightening a working load at the time of installation and reducing cost. CONSTITUTION:A heat pump type freezing cycle is formed by connecting a capability variable compressor, a four-way valve, an outdoor heat exchanger, an expansion valve and an indoor heat exchanger to one another. Further, an inverter circuit 41 for supplying a drive electric power to the compressor 1 is provided, and an output frequency of the inverter circuit 41 is controlled according to an air conditioning load. An outdoor unit A has a heat exchanger temperature sensor 11 adapted to detect a temperature of the outdoor heat exchanger, and the temperature Te detected by the heat exchanger temperature sensor 11 at the time of starting operation is used as it is as an outside air temperature To during a predetermined period of time t1 from the start of operation. After a predetermined period of time t1 elapses from the start of operation, the temperature Te detected by the heat exchanger temperature sensor 11 is corrected in accordance with an output frequency of the inverter circuit to estimate the outside air temperature To.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a function of estimating the outside temperature.

[0002]

2. Description of the Related Art An air conditioner equipped with an outside air temperature sensor for detecting the outside air temperature and performing, for example, speed control of an outdoor fan, current release control of an inverter, and correction control of a set indoor temperature according to the detected temperature. is there.

The outdoor air temperature sensor is generally attached to the outdoor unit, but it is necessary to take care so that the outdoor air temperature sensor is not affected by solar radiation or radiant heat from the outdoor heat exchanger.

[0004]

However, whether or not the outdoor air temperature sensor is affected by solar radiation is often determined by the installation condition of the outdoor unit, and it is actually difficult to select the installation location. After all, the influence of solar radiation cannot be avoided, and there is a concern that the outside temperature cannot be detected properly and operation control will be hindered.

It is conceivable that a worker selects the location where the outdoor air temperature sensor is mounted in the outdoor unit at the time of installation, but this is troublesome for the worker and there is a concern that incorrect mounting may be performed. is there.

The present invention takes the above circumstances into consideration,
The purpose is to be able to capture the outside air temperature without the need for an outside air temperature sensor, which eliminates the need for consideration of the installation location like when using an outside air temperature sensor, and can be adversely affected by solar radiation etc. It is another object of the present invention to provide an air conditioner capable of highly reliable outside air temperature detection while reducing the work load during installation and reducing the cost.

[0007]

The air conditioner of the first invention comprises a variable capacity compressor, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger to form a refrigeration cycle, and a compressor. In an air conditioner that has an inverter that supplies drive power and that controls the output frequency of this inverter according to the air conditioning load, a temperature sensor that detects the temperature of the outdoor heat exchanger and the output of the inverter for the temperature detected by this temperature sensor. Means for estimating the outside air temperature by correction according to the frequency.

The air conditioner of the second invention is an inverter for connecting a variable capacity compressor, an outdoor heat exchanger, a pressure reducer and an indoor heat exchanger to form a refrigeration cycle and supplying driving power to the compressor. In an air conditioner that controls the output frequency of this inverter according to the air conditioning load, a temperature sensor that detects the temperature of the outdoor heat exchanger and a temperature detected by the temperature sensor at the start of operation for a predetermined time from the start of operation. And a means for estimating the outside air temperature by a correction according to the output frequency of the inverter with respect to the temperature detected by the temperature sensor after a predetermined time from the start of operation.

In the air conditioner of the third invention, a variable capacity compressor, an outdoor heat exchanger, a pressure reducer and an indoor heat exchanger are connected to form a refrigeration cycle, and drive power is supplied to the compressor. In an air conditioner that includes an inverter and controls the output frequency of the inverter according to the air conditioning load, a temperature sensor that detects the temperature of the outdoor heat exchanger and a detection of the temperature sensor at the start of operation for a predetermined time from the start of operation. A means for taking the temperature as the outside air temperature, a means for estimating the outside air temperature by a correction according to the output frequency of the inverter with respect to the temperature detected by the temperature sensor after a predetermined time from the start of operation, the estimated value and the temperature sensor at the start of operation Means for obtaining the difference between the detected temperature of the temperature sensor and the means for acquiring the detected temperature of the temperature sensor at the start of operation as the outside temperature when the difference is equal to or greater than the set value, and when the difference is equal to or less than the set value And means for the first time taking in the estimated value as the outside air temperature in this, and control means for controlling the operation using the outside air temperature the taken.

An air conditioner according to a fourth aspect of the present invention is an inverter that connects a variable capacity compressor, an outdoor heat exchanger, a pressure reducer and an indoor heat exchanger to form a refrigeration cycle and supplies driving power to the compressor. And an outdoor fan that blows air to the outdoor heat exchanger, and in an air conditioner that controls the output frequency of the inverter according to the air conditioning load, the temperature sensor that detects the temperature of the outdoor heat exchanger and the drive current of the compressor are A current sensor for detecting the temperature and a means for estimating the outside air temperature by correcting the temperature detected by the temperature sensor according to the output frequency and the drive current are provided.

[0011]

In the air conditioner of the first invention, the temperature of the outdoor heat exchanger is corrected according to the output frequency of the inverter to estimate the outside air temperature. In the air conditioner of the second invention, the temperature of the outdoor heat exchanger at the start of operation is taken as the outside air temperature for a predetermined time from the start of operation, and the temperature of the outdoor heat exchanger is changed to the output frequency of the inverter after a predetermined time from the start of operation. The outside temperature is estimated according to

In the air conditioner of the third aspect of the invention, the temperature of the outdoor heat exchanger at the start of operation is taken in as the outside air temperature for a predetermined time from the start of operation, and the temperature of the outdoor heat exchanger is changed to an inverter after a predetermined time from the start of operation. The outside temperature is estimated by correcting it according to the output frequency, and the difference between this estimated value and the temperature of the outdoor heat exchanger at the start of operation is calculated.If this difference is greater than the set value, the temperature sensor at the start of operation The detected temperature is taken as the outside temperature, and when the difference becomes less than the set value, the estimated value is taken as the outside temperature for the first time, and the taken outside temperature is used for the operation control. In the air conditioner of the fourth aspect of the invention, the temperature of the outdoor heat exchanger is corrected according to the output frequency of the inverter and the drive current to estimate the outside air temperature.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 2, the outdoor unit A
And the heat pump type refrigeration cycle is mounted on the indoor unit B.

Reference numeral 1 is a variable capacity compressor, and an outdoor heat exchanger 3 is connected to a discharge port of the compressor 1 via a four-way valve 2.
An indoor heat exchanger 5 is connected to the outdoor heat exchanger 3 via an expansion valve 4 which is a pressure reducer, and the indoor heat exchanger 5
Is connected to the suction port of the compressor 1 via a four-way valve 2.

An outdoor fan 6 is provided near the outdoor heat exchanger 3, and an indoor fan 7 is provided near the indoor heat exchanger 5. The heat exchanger temperature sensor 11 is attached to the outdoor heat exchanger 3.
An indoor temperature sensor 12 is provided in the suction air passage formed by the indoor fan 7.

The control circuit is shown in FIG. The indoor control unit 20 of the indoor unit B is connected to the commercial AC power supply 30. The outdoor control unit 4 of the outdoor unit A is connected to the indoor control unit 20 via the power supply line ACL and the serial signal line SL.
0 is connected.

The indoor controller 20 comprises a microcomputer and its peripheral circuits. In this indoor control unit 20,
The light receiving unit 21, the indoor fan motor 6M, and the indoor temperature sensor 12 are connected. The light receiving unit 21 receives infrared light transmitted from a remote control type operation device (hereinafter, abbreviated as remote controller) 22.

The outdoor control unit 50 comprises a microcomputer and its peripheral circuits. The outdoor control unit 50 includes a four-way valve 2, an outdoor fan motor 6M, and a heat exchanger temperature sensor 1.
1 and the inverter circuit 41 are connected. The inverter circuit 41 rectifies the voltage of the power supply line ACL, converts it into a voltage of a predetermined frequency (and level) according to a command from the outdoor control unit 40, and outputs the voltage. This output becomes drive power for the compressor motor 1M.

Here, the indoor control unit 20 and the outdoor control unit 40 perform data transfer in synchronization with the power supply voltage through the serial signal line SL to control the air conditioner, and are provided with the following functional means.

[1] The refrigerant discharged from the compressor 1 is caused to flow in the direction of the solid arrow shown in FIG. 2 to form a cooling cycle, and the outdoor heat exchanger 3 serves as a condenser and the indoor heat exchanger 5 serves as an evaporator. Means for functioning to execute cooling operation or dry operation (= weak cooling operation).

[2] The refrigerant discharged from the compressor 1 is made to flow in the direction of the broken line arrow shown in FIG. 2 by switching the four-way valve 2, whereby a heating cycle is formed and the indoor heat exchanger 5 is replaced with a condenser and outdoor heat exchange. Means for causing the device 3 to function as an evaporator and performing heating operation.

[3] Means for switching the four-way valve 2 when the temperature detected by the heat exchanger temperature sensor 11 becomes a predetermined value or less, for example, 0 ° C. or less during heating, and performing the defrosting operation on the outdoor heat exchanger 3.

[4] During cooling and heating, the difference ΔT between the temperature Ta detected by the room temperature sensor 12 and the remote control set temperature Ts.
Is calculated as the air conditioning load, and the output frequency (the operating frequency of the compressor 1) F of the inverter circuit 41 is controlled according to the difference ΔT.

[5] Heat exchanger temperature sensor 1 at the start of operation at a predetermined time t ₁ (for example, 60 seconds) from the start of operation
A means for taking in the detected temperature Te of 1 as the outside air temperature To. [6] After a predetermined time t ₁ (for example, 60 seconds) from the start of operation,
Output temperature F of the temperature Te detected by the heat exchanger temperature sensor 11
Means for estimating the outside air temperature To according to the above.

[7] Control means for controlling the operation using the taken-in or estimated outside air temperature To. Next, the operation of the above configuration will be described with reference to FIG.
When the cooling operation is started by the remote controller 22, the temperature Te detected by the heat exchanger temperature sensor 11 is read and stored as the outside air temperature To in the memory in the control unit. At the same time, the time count t is started.

Then, the compressor 1 is started, and the refrigerant discharged from the compressor 1 passes through the four-way valve 2, the outdoor heat exchanger 3, the expansion valve 4, the indoor heat exchanger 5, and the four-way valve 2 to the compressor. Returning to 1, the cooling cycle is formed. As a result, the outdoor heat exchanger 3 functions as a condenser, the indoor heat exchanger 5 functions as an evaporator, and the room is cooled.

During this cooling, the detected temperature Ta of the indoor temperature sensor 12 is read, and the difference ΔT (= Ta-Ts) between the temperature detected by the indoor temperature sensor 12 and the set temperature Ts set by the remote controller 22 is obtained as the air conditioning load. The inverter circuit 4 has a value corresponding to the temperature difference ΔT.
The output frequency 1 (operating frequency of the compressor 1) F is set, and the capacity of the compressor 1 is controlled.

During operation, various controls are executed according to the outside air temperature To stored in the memory. For example, the speed tap of the outdoor fan motor 6M is switched according to the outside air temperature To. When the outside air temperature To is higher than the predetermined value, the current release control is performed in order to avoid the abnormal temperature rise of the inverter circuit 41. To obtain indoor comfort, the set temperature Ts is corrected according to the outside air temperature To.

After the time count t reaches the predetermined time t ₁ , the detected temperature Te of the heat exchanger temperature sensor 11 is sequentially read, and the correction value f (F (F) corresponding to the output frequency F of the inverter circuit 41 is read. ) Are sequentially read.

The correction value f (F) is a function of the output frequency F, and is stored in advance in the ROM in the control unit as the correction value setting condition shown in FIG. Further, the number of rotations of the outdoor blower 6 is stepwise (for example, three steps) according to the output frequency F.
Therefore, it is considered that the change in the rotation speed of the blower 6 is also added to this f (F). For example, when the output frequency F is 10 Hz, the correction value f (F) has a numerical value of "-
1.0 "is read out. If the output frequency F is 36 Hz, the numerical value" -7.0 "is read out as the correction value f (F).
The correction value setting conditions shown in FIG. 4 are for cooling, and of course, heating is also prepared although not shown.

The detected temperature Te is read, and the correction value f
When (F) is read, the estimated value To ₁ of the outside air temperature is obtained by the calculation of the following equation using both. To ₁ = Te + f (F) That is, between the heat exchanger temperature Te and the outside air temperature To,
As shown in FIG. 5, there is a proportional relationship with the output frequency F as a parameter. For example, when the output frequency F = 86 Hz,
There is always a difference of 9.0 ° C between the heat exchanger temperature Te and the outside air temperature To. This temperature difference is defined as the correction value f (F).

Once the estimated value To ₁ is obtained, it is the outside temperature T
It is updated and stored in the memory in the control unit as o. Thereafter, the tap switching, the current release control, and the set temperature correction described above are performed based on the estimated and updated outside air temperature To.

FIG. 6 shows the relationship between the heat exchanger temperature Te and the estimated value To _1. The proportional relationship in FIG. 5 does not hold because the operation is unstable at startup, and the estimated value To ₁ is not established. _{Although 1} greatly deviates from the actual outside air temperature, it can be understood that the estimated value To ₁ approaches the actual outside air temperature when the operation becomes stable after the start and the proportional relationship of FIG. 5 holds.

Therefore, the heat exchanger temperature Te at the time of start of operation, which is in a state substantially equal to the outside air temperature, is used as it is as the outside air temperature To for the predetermined time t ₁ from the start. Then, after the predetermined time t ₁ , the estimated value To ₁ is set as the outside air temperature To. The outside air temperature To thus obtained has a stable value that is almost equal to the actual outside air temperature, as shown in FIG.

As described above, by capturing the outside air temperature To from the heat exchanger temperature Te, the outside air temperature sensor is unnecessary. Therefore, there is no need to consider the installation location like when using an outside air temperature sensor, and there is no adverse effect of sunlight, etc., and it is possible to detect outside air temperature with high reliability while reducing the work load during installation. Become.

Moreover, the heat exchanger temperature sensor 11 is originally provided for detecting frost formation during heating, and since it is also used for detecting the outside air temperature, no additional parts are required, and the outside air temperature sensor is used. The cost can be reduced together with the elimination of the requirement.

Next, a second embodiment of the present invention will be described. Here, the indoor control unit 20 and the outdoor control unit 40
Is equipped with the following functional means. Other configurations are first
Same as the embodiment.

Here, the indoor control unit 20 and the outdoor control unit 40 perform data transfer in synchronization with the power supply voltage through the serial signal line SL to control the air conditioner, and are provided with the following functional means.

[1] The refrigerant discharged from the compressor 1 is caused to flow in the direction of the solid arrow shown in FIG. 2 to form a cooling cycle, and the outdoor heat exchanger 3 serves as a condenser and the indoor heat exchanger 5 serves as an evaporator. Means for functioning to execute cooling operation or dry operation (= weak cooling operation).

[2] The refrigerant discharged from the compressor 1 is caused to flow in the direction of the broken line arrow shown in FIG. 2 by switching the four-way valve 2, whereby a heating cycle is formed and the indoor heat exchanger 5 is used as a condenser and outdoor heat exchange. Means for causing the device 3 to function as an evaporator and performing heating operation.

[3] A means for switching the four-way valve 2 when the temperature detected by the heat exchanger temperature sensor 11 becomes a predetermined value or lower, for example, 0 ° C. or lower during heating, to execute the defrosting operation on the outdoor heat exchanger 3.

[4] The difference ΔT between the temperature Ta detected by the indoor temperature sensor 12 and the remote control set temperature Ts during cooling and heating.
Is calculated as the air conditioning load, and the output frequency (the operating frequency of the compressor 1) F of the inverter circuit 41 is controlled according to the difference ΔT.

[5] Heat exchanger temperature sensor 1 at the start of operation at a predetermined time t ₁ (for example, 60 seconds) from the start of operation
A means for taking in the detected temperature Te of 1 as the outside air temperature To. [6] After a predetermined time t ₁ (for example, 60 seconds) from the start of operation,
Output temperature F of the temperature Te detected by the heat exchanger temperature sensor 11
Means for estimating the outside air temperature To according to the above.

[7] Control means for controlling the operation using the taken-in or estimated outside air temperature To. [8] Means for obtaining the difference between the estimated value To ₁ obtained by the functional means of [6] and the temperature Te detected by the heat exchanger temperature sensor 11 at the start of operation after a predetermined time t ₁ from the start of operation.

[9] The calculated difference is the set value α (for example, 2
℃) or more, heat exchanger temperature sensor 11 at the start of operation
A means for taking in the detected temperature Te as the outside air temperature To. [10] A means for taking the estimated value To ₁ as the outside air temperature To for the first time when the calculated difference becomes equal to or less than the set value α.

Next, the operation of the above configuration will be described with reference to FIG. At the start of operation, first, the flag flag in the control unit is set to "0". And the heat exchanger temperature sensor 1
The detected temperature Te of 1 is stored in the memory in the control unit as the outside air temperature To. This continues at least until a predetermined time t ₁ has elapsed from the start of operation.

When a predetermined time t ₁ has passed from the start of operation,
The detected temperature Te of the heat exchanger temperature sensor 11 is sequentially read, and the correction value f (F) corresponding to the output frequency F of the inverter circuit 41 is sequentially read.

Then, for the detected temperature Te to be read,
The read correction value f (F) is added to obtain the estimated value To ₁ of the outside air temperature. To ₁ = Te + f (F) When the estimated value To ₁ is obtained, the outside temperature To that has already been stored (that is, the heat exchanger temperature sensor 1 at the start of operation)
The difference (= To ₁ −To) from the detected temperature Te of ₁ ) is obtained.

If this difference (absolute value) is not less than the set value α,
Under the judgment that the operation is not stable yet, the already stored outside air temperature To is continuously valid as it is. When the difference becomes equal to or less than the set value α, the estimated value To ₁ is updated and stored as the outside air temperature To for the first time under the judgment that the operation is stable. After that, the flag flag is set to "1", and the estimated and updated outside air temperature To becomes valid.

The effect is the same as that of the first embodiment, but in particular, the determination as to whether or not to take in the estimated value To ₁ as the outside air temperature To is made by the two-step preparation of the elapsed time and the magnitude of the estimated value To _1. Therefore, the effect that the reliability as the outside air temperature To is improved is added.

Next, a third embodiment of the present invention will be described. In this embodiment, in addition to the first and second embodiments, the outside air temperature To is estimated by considering the refrigerant gas amount in the refrigeration cycle.

Here, as shown in FIG. 9, the outdoor unit A is provided with a current sensor 42, and the current sensor 42 is a current of the power supply line ACL between the outdoor control section 40 and the inverter circuit 41. The value is detected, and the detection result (detection current Iin) is sent to the outdoor control unit 40.

The indoor control unit 20 and the outdoor control unit 40 have the following functional means. [1] The refrigerant discharged from the compressor 1 is caused to flow in the direction of the solid line arrow shown in FIG. 2, whereby a cooling cycle is formed and the outdoor heat exchanger 3 functions as a condenser and the indoor heat exchanger 5 functions as an evaporator. Means for performing cooling operation or dry operation (= weak cooling operation).

[2] The refrigerant discharged from the compressor 1 is caused to flow in the direction of the broken line arrow shown in FIG. 2 by switching the four-way valve 2, whereby a heating cycle is formed and the indoor heat exchanger 5 is used as a condenser and outdoor heat exchange. Means for causing the device 3 to function as an evaporator and performing heating operation.

[3] Means for executing the defrosting operation on the outdoor heat exchanger 3 when the temperature detected by the heat exchanger temperature sensor 11 becomes a predetermined value or less, for example, 0 ° C. or less during heating, and the four-way valve 2 is switched.

[4] The difference ΔT between the temperature Ta detected by the indoor temperature sensor 12 and the remote control set temperature Ts during cooling and heating.
Is calculated as the air conditioning load, and the output frequency (the operating frequency of the compressor 1) F of the inverter circuit 41 is controlled according to the difference ΔT.

[5] Heat exchanger temperature sensor 1 at the start of operation at a predetermined time t ₁ (for example, 5 minutes) from the start of operation
A means for taking in the detected temperature Te of 1 as To. [6] After a predetermined time t ₁ (for example, 5 minutes) from the start of operation,
A means for reading the first correction value f (F) according to the output frequency F (and the outdoor fan rotation speed rps).

[7] After a predetermined time t ₁ (for example, 5 minutes) from the start of operation, based on the detection current Iin of the current sensor 42,
A means for reading out the refrigerant gas amount according to the output frequency F. [8] A means for reading the second correction value f (I) based on the refrigerant gas amount.

[9] The estimated value To ₁ of the outside air temperature is obtained based on the first correction value f (F), the second correction value f (I), and the temperature Te detected by the heat exchanger temperature sensor 11. means. [10] A means for updating and storing the estimated value To ₁ as To.

[11] Control means for controlling the operation using the updated outside air temperature To. Next, the operation of the above configuration will be described with reference to FIG. When the start operation of the cooling operation is performed by the remote controller 22,
The temperature Te detected by the heat exchanger temperature sensor 11 is read and stored as the outside air temperature To in the memory in the control unit.
At the same time, the time count t is started.

Then, the compressor 1 is started, and the refrigerant discharged from the compressor 1 passes through the four-way valve 2, the outdoor heat exchanger 3, the expansion valve 4, the indoor heat exchanger 5, and the four-way valve 2 to the compressor. Returning to 1, the cooling cycle is formed. As a result, the outdoor heat exchanger 3 functions as a condenser, the indoor heat exchanger 5 functions as an evaporator, and the room is cooled.

During this cooling, the detected temperature Ta of the indoor temperature sensor 12 is read, and the difference ΔT (= | Ta-Ts |) between the temperature detected by the remote controller 22 and the set temperature Ts is obtained as the air conditioning load. The output frequency (the operating frequency of the compressor 1) F of the inverter circuit 41 is set to a value corresponding to this temperature difference ΔT, and the capacity of the compressor is controlled.

During operation, various controls are executed in accordance with the outside air temperature To stored in the memory, as in the first embodiment. After the time count t reaches the predetermined time t ₁ ,
The detection temperature Te of the heat exchanger temperature sensor 11 and the detection current Iin of the current sensor 42 are sequentially read, and at the same time, a correction value f corresponding to the output frequency F of the inverter circuit 41 is obtained.
(F) and f (I) are sequentially read.

The correction value f (F) is a function of the output frequency F as shown in FIG. 11, and is stored in advance in the ROM in the control unit as the correction value setting condition, as in the first embodiment.

The correction value f (I) is a function of the refrigerant gas amount as shown in FIG. 13, and the refrigerant gas amount has a correlation with the detected current Iin of the current sensor 42 as shown in FIG. . As shown in FIG. 12, when the amount of refrigerant gas changes, the load acting on the compressor 1 also changes, and the current value required to drive the compressor 1 (detection current Iin of the current sensor 42) also changes.
The relationship between the refrigerant gas amount and the current Iin is the output frequency F
It differs depending on (F _{1 to} F ₃ ). Then, as shown in FIG. 13, if f (I) is known, the refrigerant gas amount is determined. That is, f (I) decreases as the refrigerant gas amount decreases. These correlations are stored in advance in the ROM in the control unit.

In order to prevent the figure from becoming complicated, the relationship between the refrigerant gas amount and the current Iin is set in three stages (F ₁ to F _1).
3 shows only) for but actually the relationship between potential refrigerant gas amount for all the frequency and current Iin to operate is stored. The correction value setting conditions shown in FIGS. 12 and 13 are for cooling, and of course, heating is also prepared although not shown.

When the detected temperature Te is read and the correction values f (F) and f (I) are read, the estimated value To ₁ of the outside air temperature is obtained by the calculation of the following equation using both. To ₁ = Te + f (F) + f (I) FIG. 14 shows this relationship. To ₁ is proportional to Te. As the amount of refrigerant decreases, f (I) increases.

As described above, in this embodiment,
The temperature of the outdoor heat exchanger 3, the output frequency of the compressor 1, and
Since the outside air temperature is set based on the amount of the refrigerant gas, the outside air temperature can be detected while preventing the influence of the amount of the refrigerant gas in addition to the effect similar to that of the first embodiment. Therefore,
It is possible to further improve the estimation accuracy of the outside air temperature detection regardless of the amount of the refrigerant enclosed in the refrigeration cycle during installation. The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

[0069]

As described above, according to the first to fourth aspects of the invention, since the outside air temperature is estimated from the temperature of the outdoor heat exchanger, the outside air temperature can be calculated without using the outside air temperature sensor. This eliminates the need for consideration of the installation location like when using an outside air temperature sensor, and is not affected by the effects of sunlight, etc., reducing the work load during installation and reducing the cost. However, it is possible to provide an air conditioner capable of highly reliable detection of the outside air temperature.

[Brief description of drawings]

FIG. 1 is a block diagram of a control circuit according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a refrigeration cycle of the same embodiment.

FIG. 3 is a flowchart for explaining the operation of the embodiment.

FIG. 4 is a diagram showing a format of a correction value setting condition of the embodiment.

FIG. 5 is a diagram showing a proportional relationship between the heat exchanger temperature and the outside air temperature in the embodiment.

FIG. 6 is a diagram showing a relationship between a heat exchanger temperature and an estimated value in the same example.

FIG. 7 is a diagram showing changes in outside air temperature obtained in the same example.

FIG. 8 is a flow chart for explaining the operation of the second embodiment of the present invention.

FIG. 9 is a block diagram of a control circuit according to a third embodiment of the present invention.

FIG. 10 is a flowchart for explaining the operation of the embodiment.

FIG. 11 is a diagram showing a proportional relationship between the heat exchanger temperature and an estimated value in which only the output frequency is taken into consideration in the example.

FIG. 12 is a diagram showing the relationship between the drive current and the amount of refrigerant in the embodiment.

FIG. 13 is a diagram showing a relationship between a refrigerant gas amount and a second correction value in the example.

FIG. 14 is a diagram showing a proportional relationship between a heat exchanger temperature and an estimated value in consideration of an output frequency and a refrigerant gas amount in the example.

[Explanation of symbols]

1 ... Variable capacity compressor, 3 ... Outdoor heat exchanger, 5 ... Indoor heat exchanger, 11 ... Heat exchanger temperature sensor, 12 ... Indoor temperature sensor, 20 ... Indoor control unit, 40 ... Outdoor control unit, 41 ... Inverter Circuit, 42 ... Current sensor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobusuke Shirakawa 336 Tatehara, Fuji City, Shizuoka Prefecture, Toshiba Corp., Fuji Factory (72) Inventor Atsushi Nagasawa 336 Tatehara, Fuji City, Shizuoka Corporation, Fuji Plant, Toshiba (( 72) Inventor Naoki Omura 336 Tatehara, Fuji City, Shizuoka Prefecture, Toshiba Corp., Fuji Factory (72) Inventor Toshiyuki Uemura 336 Tatehara, Fuji City, Shizuoka Prefecture, Fuji Plant, Toshiba (72) Inventor, Hitoshi Konemura Fuji, Shizuoka Prefecture 336 Tatehara City, Toshiba Fuji Factory

Claims (4)

[Claims] 1. A variable capacity compressor, an outdoor heat exchanger, a pressure reducer, an indoor heat exchanger are connected to form a refrigeration cycle, and an inverter is provided for supplying drive power to the compressor.
In an air conditioner that controls the output frequency of the inverter according to the air conditioning load, a temperature sensor that detects the temperature of the outdoor heat exchanger, and the detected temperature of the temperature sensor are corrected according to the output frequency to obtain the outside air temperature. And an air conditioner for estimating. 2. A variable capacity compressor, an outdoor heat exchanger, a pressure reducer, an indoor heat exchanger are connected to form a refrigeration cycle, and an inverter is provided for supplying drive power to the compressor.
In an air conditioner that controls the output frequency of this inverter according to the air conditioning load, a temperature sensor that detects the temperature of the outdoor heat exchanger and a temperature that is detected by the temperature sensor at the start of operation for a predetermined time from the start of operation An air conditioner comprising: a unit for taking in the temperature as an air temperature; and a unit for estimating the outside air temperature by correcting the temperature detected by the temperature sensor according to the output frequency after a predetermined time from the start of operation. 3. A variable capacity compressor, an outdoor heat exchanger, a pressure reducer, an indoor heat exchanger are connected to form a refrigeration cycle, and an inverter is provided for supplying drive power to the compressor.
In an air conditioner that controls the output frequency of this inverter according to the air conditioning load, a temperature sensor that detects the temperature of the outdoor heat exchanger and a temperature that is detected by the temperature sensor at the start of operation for a predetermined time from the start of operation Means for taking in as the air temperature, means for estimating the outside air temperature by correcting the detected temperature of the temperature sensor according to the output frequency after a predetermined time from the start of operation, and the estimated value and the temperature sensor at the start of operation. A means for obtaining a difference from the detected temperature, a means for taking the detected temperature of the temperature sensor at the start of operation as the outside air temperature when the difference is a set value or more, and the estimation for the first time when the difference becomes the set value or less. An air conditioner comprising: a unit that takes in a value as an outside air temperature; and a control unit that controls the operation using the taken outside air temperature. 4. A variable capacity compressor, an outdoor heat exchanger, a pressure reducer, an indoor heat exchanger are connected to form a refrigeration cycle, and an inverter is provided for supplying drive power to the compressor.
In an air conditioner that controls the output frequency of the inverter according to an air conditioning load, a temperature sensor that detects the temperature of the outdoor heat exchanger, a current detection unit that detects a drive current of the compressor, and a temperature sensor of the temperature sensor. An air conditioner, comprising: means for correcting the detected temperature according to the output frequency and the drive current to estimate the outside air temperature.